This is a longitudinal investigation over a five-year period of two samples of Manhattan families and their children, one a random Cross-section sample (N equals 1034) and the other a Welfare sample (N equals 1000) seleced randomly from four Welfare centers. 73% of the Cross-section and 67% of the Welfare samples were reinterviewed at the follow-up point. The study objective is to specify the relations between environmental stress and strain (as evidenced by behavioral disorders) in urban children. The study has determined the age-developmental trends shown by various behaviors and their internal predictability over time and is presently determining the long-term predictive power of various stresses (social-demographic, parental and parent-child) for disorder. Also in progress is the investigation of those changes in stresses associated with changes in different types of behavioral impairment. In addition, the impact of intervening events or change relative to the impact of continuing stressful processes will be studied. Incidence and spontaneous recovery rates of disorders are being determined. Validity issues will be handled by comparing the same information from multiple sources - the mother, the child himself, and the school. The relative contributions of child personality and environmental stresses to school performance will be determined.